§ 15.01.1230. Concrete in cold weather.

When the atmospheric temperature may be expected to drop below forty degrees Fahrenheit at the time concrete is delivered to the work site, during placement, or at any time during the curing period, the following provisions may also apply:

1.

The temperature of the concrete at time of placing shall not be less than fifty degrees Fahrenheit nor more than ninety degrees Fahrenheit. The temperature of neither aggregates nor mixing water shall be more than one hundred degrees just prior to mixing with the cement.

2.

When the daily minimum temperature is less than forty degrees Fahrenheit, concrete structures shall be insulated or housed and heated after placement. The temperature of the concrete and air adjacent to the concrete shall be maintained at not less than fifty degrees Fahrenheit nor more than ninety degrees Fahrenheit for the duration of the curing period.

3.

Method of insulation shall be by standard concrete insulation blankets, or straw. When using straw the contractor shall have a bottom and top layer of visqueen with six inches of straw between visqueen layers. Methods of insulating, housing and heating the structure shall conform to "Recommended Practice for Cold Weather Concreting," ACI Standard 306.

4.

When dry heat is used to protect concrete, means of maintaining an ambient humidity of at least forty percent shall be provided unless the concrete has been coated with curing compound or is covered with an approved impervious material.

5.

Equipment for protecting concrete from freezing shall be available at the job site prior to placing concrete. Particular care shall be exercised to protect edges and exposed corners from freezing. The housing covering or other protection used, shall remain in place and intact at least twenty-four hours after the heating is discontinued.

(Ord. No. 2007-07-31, § 12.18, 7-10-2007)